The horns of the art produce a sound by the membrane, which is vibrated by a pressure fluid, generally air. Such horns are generally used as ship horns or sirens in factories etc. Accordingly, they are generally of considerable dimensions and weight, thus a relatively high pressure is needed for producing a very strong sound.
The Hungarian patent 89 973, 95 819, 98 353, 100 289 and 101 300 all disclose such horns. The membranes of these horns are of metal sheets and are prestressed. The pipe introducing the pressure fluid is always arranged at the central part of the membrane, meanwhile a sound tube or horn is coaxial with the pressure tube and the end thereof bearing the membrane is arranged around the pressure tube.
On the other hand, people at sporting events, (for instance football matches) or festivals often use horns made of paper.
These horns produce, however, a rather poor sound.